Question

Q. Which of the following correctly points out the difference between the earthquakes witnessed in Alpine-Himalayan belts (AHB) and those in Mid-oceanic ridges (MOR)?

• A.
  In MOR most earthquakes are largely tectonic in origin whereas in AHB they are reservoir induced.
• B.
  In AHB most earthquakes occur due to frequent avalanches whereas In MOR they are caused due to reservoir convergence.
• C.
  In AHB the foci of earthquakes are deeper than that of the MOR earthquakes.
• D.
  None of the above

Answer 1

The correct option is C

In AHB the foci of earthquakes are deeper than that of the MOR earthquakes.
Explanation:

In general, the foci of the earthquake in the areas of mid-oceanic ridges are at shallow depths whereas along the Alpine-Himalayan belt as well as the rim of the Pacific, the earthquakes are deep-seated ones.
The reason for this is: In Mid-oceanic ridges, some of these earthquakes are caused by volcanic eruptions, and others are caused by breaking and ripping of the thin, newly created plate as it spreads to either side of the ridge. But, in Alpine-Himalayan region heavy plate tectonics is at work, and causes massive deep-seated earthquakes.
Both regions come under the Ring of Fire.